Abstract : The bottleneck of long-term Wireless Sensor Network (WSN) applications is typically the energy. A promising solution is to enable each node to harvest energy directly in its environment, using individual energy harvesters. In energy harvesting WSNs, an important issue is the online adaptation of the node power consumption to avoid power failures while maintaining a good quality of service. This management is implemented on each node by an Energy Manager (EM). In this demonstration, Fuzzyman, a novel EM relying on fuzzy control theory, is applied to indoor light energy harvesting. The online adaptation of Fuzzyman is shown in terms of packet rate generation.